1. Field of the Invention
The present invention relates to a method of taking up and setting down, respectively of package-like articles from and onto, respectively a support by means of a horizontally displaceable receiving table, which receiving table includes at least at its top surface an article transporting device adapted to be driven and includes a roller or guide-roller like pick-up member located at least at its end facing its direction of travel.
The invention relates further to an apparatus for taking up and setting down, respectively package-like articles from and onto, respectively a support.
2. Description of the Prior Art
Such apparatuses are known as so-called depalletizer apparatuses such as, for instance, disclosed in the German specification DE-OS 26 31 942. These apparatuses are used to remove package-like articles such as boxes, crates and similar articles from a storage thereof. A roller is brought into contact with the side of an article, such that the article is lifted up by means of a frictional engagement, gripped by a transporting device and transported off. The problem here encountered is to avoid damaging of the article to be picked up or of its packaging and, on the other hand, to guarantee a defined and safe picking up procedure.
For this reason the pick-up roller of the above mentioned German specification is supported in a horizontal plane elastically at a carriage, so that during a moving of the carriage in the direction of the article, an increasingly rising friction lifting force is exerted onto the article. After the pick-up roller has rotated during a prolonged time span with an increasing friction lifting force in contact with the article, this article is grasped at an undetermined instant of time and position of the carriage, and the roller, which is now is in a biassed state, snaps under the article.
This procedure leads specifically in the case of sensitive articles or packagings, to easily damaging the articles; with at least traces of the frictional engagement remaining upon the articles. Depending on prevailing weights of the articles, the roller which snaps forward can push the articles out of their balance or equilibrium, respectively, and displace them on their support or even damage them. Furthermore, the instant, where the picking up begins, is uncertain, which renders an automatization of the entire procedure quite difficult.
Other suggestions for such apparatuses have also been made, which suggestions entail designs, according to which these apparatuses must be positioned for taking up the articles exactly at the level of the bottom edge of the article (see e.g. U.S. Defense publication T 998,009), which procedure renders an automatization almost impossible. A not extremely precise positioning in the level leads again to a damaging of the article, which additionally in such case cannot be picked up.
Finally, the German specification DE-AS 2 137 827 discloses a depalletizing method for certain shapes of beverage crates and a pick-up apparatus which operates at a frictional contact and has the shape of a ramp, which apparatus cooperates with a lifting device, such to bring the crates into the path of movement of a conveyor which moves continuously forward. This apparatus is designed for very specific crates only and is, furthermore, based on the fact that the crates are displaced relative to their support during the lifting thereof.
None of the apparatuses mentioned above is, furthermore, in a position to set the articles which have been picked up again down at a predetermined location.